The present disclosed preferred embodiment concerns a cleaning unit and a method for cleaning a transport belt for transport of recording media in the transfer printing region of an electrographic printing or copying device, as well as an abrasion element and a capture reservoir for such a cleaning unit.
In electrographic printers or copiers, the transfer of a toner image from an intermediate carrier (for example a photoconductor drum or a photoconductor ribbon) onto a recording medium is designated as transfer printing. The section of the printing or copying device at which the intermediate carrier and the recording medium are brought into contact with one another is designated as a transfer printing region. In the transfer printing region, the intermediate carrier (meaning, for example, the generated surface of a photoconductor drum) and the recording medium move in the same direction with the same speed while the toner is transferred from the intermediate carrier onto the recording medium. A print image of high quality can only be achieved on the recording medium when a uniform contact between recording medium and intermediate carrier is produced in the transfer printing region and when the recording medium and the intermediate carrier actually move with exactly the same speed in the transfer printing region.
In order to ensure this, transport belts are proposed on which the recording media (for example electrostatically adhering) are transported through the transfer printing region. With such a transport belt, the transport speed of the recording medium in the transfer printing region can be predetermined exactly and without interference, and a uniform arrangement of the recording medium on the intermediate carrier can be achieved. Since the transport belt moves through the transfer printing region, it can easily be contaminated with toner. When, for example, individual paper sheets are used as recording media, toner can arrive on the intermediate regions between successive sheets and in the boundary regions outside of the paper dimension. In the event that the recording medium is printed on both sides, toner can moreover loosen from an already-printed side with which the recording medium lies on the transport belt and contaminate this. A transport belt contaminated with toner in turn contaminates subsequent recording media, which is not acceptable.
A cleaning unit is known from DE 198 31 786 A1 that has an abrasion element (arranged transverse to the running direction of the transport belt and lying on this) that is set to abrade toner located on a transport belt and that has a toner capture reservoir for capture of the abraded toner.
An abrasion element for a photoconductor drum is known from JP 03-200191. The abrasion element is comprised of a synthetic rubber that is admixed with 1 weight percent aluminum oxide as a polishing agent. A further abrasion element for a photoconductor drum is known from EP 0 691 594 A1. Rubber, plastic, metal and ceramic are cited therein as materials for the abrasion element. The material rubber is thereby preferred.
A cleaning unit with a mounting device for an abrasion element that is rotatable by 180° is known from EP 0 546 751 A2. Various edges of the abrasion element can thereby be used for cleaning. Toner capture reservoirs are disclosed in U.S. Pat. Nos. 4,730,205, 6,405,016 B1, 5,581,342 4,500,196 and 5,383,011.